In the teaching program of the welding system for performing welding by the robot, in general, a torch target position and a torch orientation are registered as an operation instruction. In addition, welding parameters such as a welding current and a welding voltage are registered as a welding instruction. Since the operation instruction relates to the torch target position and torch orientation, the operation instruction is controlled by the robot. Since the welding instruction relates to the welding parameters such as the welding current and the welding voltage, the welding instruction is controlled by a welding device. Thus, the operation instruction and the welding instruction are instructions of different natures, and not registered in the same line in the teaching program. That is, the operation instruction and the welding instruction are registered in lines different and away from each other in the teaching program of the welding system. The torch target position, the torch orientation, and the welding parameters (welding current, welding voltage, or the like) are collectively referred to as a welding condition.
A technology which relates to the offline teaching device for automatically teaching the teaching program of such a welding system, and creates the teaching program under a condition where a robot operation pattern and a database of the welding parameters are prepared is known (see PTL 1).